Methods for repairing low-k dielectrics using carbon plasma immersion

Abstract

Methods for repairing low-k dielectrics using a plasma immersion carbon doping process are provided herein. In some embodiments, a method of repairing a low-k dielectric material disposed on a substrate having one or more features disposed through the low-k dielectric material may include depositing a conformal oxide layer on the low-k dielectric material and within the one or more features; and doping the conformal oxide layer with carbon using a plasma doping process.

We claim: 
     
       1. A method of repairing a dielectric material disposed on a substrate having one or more features disposed through the dielectric material, comprising:
 depositing a conformal oxide layer on the dielectric material and within the one or more features; and 
 subsequently, doping the conformal oxide layer with carbon, using a plasma doping process, wherein carbon is implanted through the conformal oxide layer and into the dielectric material. 
 
     
     
       2. The method of  claim 1 , wherein the conformal oxide layer comprises silicon dioxide or carbon doped silicon oxide. 
     
     
       3. The method of  claim 1 , wherein the substrate further comprises a dielectric layer comprising the dielectric material, a hard mask layer disposed beneath the dielectric layer, and a conductive layer disposed beneath the hard mask layer, and wherein the one or more features further comprises a via disposed through the dielectric layer and the hard mask layer to expose a surface of the conductive layer, and further comprising:
 removing the conformal oxide layer from a bottom surface of the one or more features to expose a portion of the conductive layer; and 
 filling the one or more features with a conductive material. 
 
     
     
       4. The method of  claim 3 , wherein the dielectric material has a k value range of about 2.2 to about 2.5. 
     
     
       5. The method of  claim 3 , wherein the conductive layer comprises at least one of copper, aluminum, and alloys thereof. 
     
     
       6. The method of  claim 1 , wherein depositing the conformal oxide layer further comprises:
 depositing the conformal oxide layer in a chemical vapor deposition (CVD) process or plasma enhanced atomic layer deposition (PEALD). 
 
     
     
       7. The method of  claim 6 , wherein the CVD or PEALD process is repeated until the thickness of the conformal oxide layer is about 20 to about 70 angstroms. 
     
     
       8. The method of  claim 1 , wherein thickness of the conformal oxide layer is less than about 100 angstroms. 
     
     
       9. The method of  claim 1 , wherein doping the conformal oxide layer further comprises:
 exposing the substrate to an inductively formed plasma comprising carbon; and 
 applying a bias voltage to the substrate. 
 
     
     
       10. The method of  claim 9 , wherein doping the conformal oxide layer is performed in a plasma immersion ion implantation reactor. 
     
     
       11. The method of  claim 9 , wherein exposing the substrate to the inductively formed plasma comprises providing a process gas comprising carbon to a process chamber having the substrate disposed therein and forming a plasma from the process gas. 
     
     
       12. The method of  claim 11 , wherein the process gas comprises at least one carbon containing gas comprising methane (CH 4 ), ethylene (C 2 H 4 ), ethane (C 2 H 6 ), or propane (C 3 H 8 ). 
     
     
       13. The method of  claim 11 , wherein the carbon containing process gas is diluted with an inert gas, and wherein the dilution of the carbon containing process gas controls a carbon profile in the conformal oxide layer. 
     
     
       14. The method of  claim 9 , wherein exposing the substrate to the inductively formed plasma comprises providing up to about 1000 W of RF power at a frequency of about 13.56 MHz to form the plasma. 
     
     
       15. The method of  claim 9 , wherein doping the conformal oxide layer further comprises biasing the substrate with up to about 5000 W of RF power at a frequency of about 2 MHz. 
     
     
       16. The method of  claim 9 , wherein doping the conformal oxide layer further comprises maintaining the substrate temperature in the range of about 5 degrees Celsius to about 100 degrees Celsius. 
     
     
       17. The method of  claim 9 , wherein doping the conformal oxide layer further comprises implanting about 25 to about 40 atomic percent carbon in the conformal oxide layer. 
     
     
       18. The method of  claim 1 , further comprising:
 processing the substrate in a manner that depletes at least some carbon from the dielectric material prior to depositing the conformal oxide layer. 
 
     
     
       19. A method of repairing a low-k dielectric material disposed on a substrate comprising a conductive layer, a hard mask layer disposed over the conductive layer, and a low-k dielectric layer disposed over the hard mask layer, wherein one or more features are disposed through the low-k dielectric layer and the hard mask layer to expose a surface of the hard mask layer, the method comprising:
 depositing a conformal oxide layer comprising silicon dioxide on the dielectric material and within the one or more features; 
 subsequently, doping the conformal oxide layer with carbon, using a plasma doping chamber, wherein carbon is implanted through the conformal oxide layer and into the dielectric material; 
 removing the conformal oxide layer from a bottom surface of the one or more features; and 
 filling the one or more features with a conductive material. 
 
     
     
       20. A method of repairing a dielectric material disposed on a substrate having one or more features disposed through the dielectric material, comprising:
 depositing a conformal oxide layer on the dielectric material and within the one or more features; and 
 subsequently, doping the conformal oxide layer with carbon, using a plasma doping process, wherein the k value of the conformal oxide layer is greater than the k value of the dielectric material.